Flash Heat Wave Monday, Questions About Heat And Storms Today, Then Sharply Cooler Late Week

NOAA's Storm Prediction Center still extends their
slight risk of severe thunderstorms into Vermont.
(Everything in yellow is a slight risk).

That was a wild weather ride on Monday! 

Northern Vermont in particular endured the day's weather whiplash. As I noted in yesterday morning's post, the day began stormy and cold with fitful downpours, local gusty winds and even a rumble or two of thunder. 

Burlington reached 90 degrees by late afternoon, after a rainy early morning low of 51 degrees. By afternoon, we were sweating in a brief May heat wave that is already over-performing. 

I saw somewhere on social media where somebody in Vermont said they ran their furnace in the morning and air conditioner in the afternoon.

I'd call it a flash heat wave. Like a sudden flash flood, only hot air, not water. 

The day featured a rare temperature stat: Burlington had its first 80 degree temperature of the season Sunday. And only a day later, the first 90 of the season hit.  The same thing happened in April, 2002, but I wonder if this week and 2002 were the only times something like that happened. 

There has always been the occasional May in Burlington in which the temperature hit 90. But probably at least in part due to climate change, 90 degree May days are getting more common. In the 109 years in Burlington ending in 2009, we had 14 Mays that reached at least 90 degrees.

But in the 16 years since 2010, there have already been eight such days in May.  

Elsewhere in Vermont, the high in Bennington Monday was 89 degrees. Montpelier reached 86 degrees after a morning low of 46.  A temperature change of 40 degrees in just one day is pretty wild. 

The heat isn't only a Vermont thing, of course. Philadelphia reached 96 degrees Monday, a record for the date. It was also the second hottest May temperature on record.  In New York City, a high of 95 is expected today, followed by an incredibly stuffy overnight low tonight of 77. It should hit 90 degrees in the Big Apple again tomorrow. 

Heat advisories are in effect for much of southern New England and the Mid-Atlantic states. Hartford, Connecticut had its second day in a row of 90 degree temperatures Monday. Today's forecast high there is a whopping 96 degrees. The forecast high in Springfield today is 97.

VERMONT FORECAST

Back here in Vermont, the degree of heat today will depend on the level of cloud cover.  Severe thunderstorms are also possible, but there might be factors that allow us to luck out and avoid the worst of the storms. Maybe. 

We're certainly off to a very warm, muggy start. It looks like the low temperature this morning in Burlington was 71 degrees, so if you didn't sleep well in the Champlain Valley, that's why. If that low temperature holds through midnight, it'll break the record for warmest low temperature for the date. (The current record holder is 67 degrees way back in 1903.  

As the day goes on the valleys of southern Vermont have the best chance of reaching 90 degrees today, as they'll have the most sun.  The National Weather Service forecast for Springfield, for instance is 92 degrees.

I think clouds might prevent another 90 degree day in Burlington today, we'll see about that. There was already a batch of clouds and light showers in central and western New York early this morning. Those clouds might not clear out fast enough to allow another 90 degree day. Though we're starting out pretty warm, so it's still possible. 

The next question is severe thunderstorms. 

NOAA's Storm Prediction Center still has a slight risk - level 2 alert on a scale of 5 - for the northwest half of Vermont and a level one marginal risk for the southeast. 

The amount of instability in the atmosphere over us isn't huge over us today, which is a limiting factor for storms. But there is a subtle disturbance in the atmosphere due by early afternoon. That, combined with rising air near mountains could trigger some storms.

Also, cool air coming off of Lake Champlain sometimes creates these teeny tiny miniature cold fronts which are boundaries between the cool lake air and the warmer inland air. Those could be triggering spots for storms. After that, cool winds blasting out of thunderstorms could set up additionally teeny tiny little cold fronts elsewhere, which would trigger more storms. 

Bottom line: Some of us will see showers or storms, some of us will stay dry.  A small number of us could experience strong, even damaging winds from storms. This won't be a widespread severe storm event. 

We don't know who, if anybody will get those rambunctious storms. Pay attention to the skies if you're outdoors, and have a way to receive severe storm warnings, just in case. 

TONIGHT/TOMORROW

After another stuffy night coming up, Wednesday will bring another big change. A cold front will stumble through, in the morning north, afternoon south and east. The timing of it means the north will probably just see some scattered showers in the morning, with clearing skies and highs in the 70s during the afternoon. 

Southeast Vermont could see some thunderstorms but severe ones seem unlikely, at least for now. Highs in the south look like they want to get up into the 80s

THURSDAY/FRIDAY

More big changes in a roller coaster of a weather week. We'll wake up to sharply colder temperatures Thursday morning with lows in the 38 to 45 degrees. Under at least partly sunny if not clear skies, temperatures should only get into the mid and upper 50s north,  and some 60s south. 

Since it will be so cool, there might be some frost Thursday night and early Friday in areas of Vermont away from the Champlain Valley.

MEMORIAL DAY WEEKEND

A toss up on how the holiday weekend will turn out. The American weather model keeps showers at bay Saturday and Sunday, leaving us with partly sunny skies and cool highs in the 60s.  The European model brings showers into our area Saturday and Sunday. Both models give us some showers on Monday, Memorial Day.